... cycle (O–UC) enzyme activity and mRNA expression,we subjected toadfish to two-day and seven-day crowding regimes. Plasma cortisol levels were measured and liver tissue was assayed for ammonia and urea concentrations. Liver glutamine synthetase (GS), carbamoyl phosphate synthetase III (CPS), ornithine...

... in the various tissues of H. signifer exposed to environmental ammonia despite a significant increase in the hepatic glutamine synthetase activity. These results indicate that the excess glutamine formed was channelled completely into urea formation through carbamoyl phosphate synthetase III. It has been...

[email protected] ) 21 7 2003 © The Company of Biologists Limited 2003 2003 amino acid ammonia arginase carbamoyl phosphate synthetase dipnoan lungfish glutamine synthetase ornithine-urea cycle Protopterus dolloi urea urea transporter The fish-tetrapod transition represents...

... of the key urea cycle enzyme, carbamoyl phosphate synthetase III (CPSase III), and other enzymes in the pathway, whereas adult trout had much lower or non-detectable activities. The present study tested the hypothesis that urea cycle enzyme expression is unique to early stages of rainbow trout. In marine...

... for an ammoniotelic teleost ( Micropterus salmoides , the largemouth bass) and an obligate ureogenic elasmobranch ( Squalus acanthias , the dogfish shark). The present study documents the expression of mitochondrial carbamoyl phosphate synthetase (CPSase) III and cytosolic CPSase II (and its associated enzymes...

... just after hatching and the levels of activity increased markedly to day 93. Carbamoyl phosphate synthetase (CPSase) and ornithine transcarbamylase (OTCase) were first detected in 40-day-old embryos; activities peaked between days 53 and 71 and then subsequently decreased. Adult liver enzyme activity...